From 556135d8139dfe8ea91927bcb82395301ffb1322 Mon Sep 17 00:00:00 2001
From: Akira Hatanaka <ahatanaka@mips.com>
Date: Wed, 6 Feb 2013 21:50:15 +0000
Subject: [PATCH] [mips] Make NOP a pseudo instruction and expand it to "sll
 $zero, $zero, 0".

llvm-svn: 174546
---
 llvm/lib/Target/Mips/MipsAsmPrinter.cpp  | 13 ++++++-------
 llvm/lib/Target/Mips/MipsInstrFormats.td |  6 ------
 llvm/lib/Target/Mips/MipsInstrInfo.td    |  3 +--
 3 files changed, 7 insertions(+), 15 deletions(-)

diff --git a/llvm/lib/Target/Mips/MipsAsmPrinter.cpp b/llvm/lib/Target/Mips/MipsAsmPrinter.cpp
index 07a4faa..e573e89 100644
--- a/llvm/lib/Target/Mips/MipsAsmPrinter.cpp
+++ b/llvm/lib/Target/Mips/MipsAsmPrinter.cpp
@@ -66,19 +66,18 @@ void MipsAsmPrinter::EmitInstruction(const MachineInstr *MI) {
     return;
   }
 
-  // Do any auto-generated pseudo lowerings.
-  if (emitPseudoExpansionLowering(OutStreamer, MI))
-    return;
-
   MachineBasicBlock::const_instr_iterator I = MI;
   MachineBasicBlock::const_instr_iterator E = MI->getParent()->instr_end();
 
   do {
-    MCInst TmpInst0;
-    MCInstLowering.Lower(I++, TmpInst0);
+    // Do any auto-generated pseudo lowerings.
+    if (emitPseudoExpansionLowering(OutStreamer, &*I))
+      continue;
 
+    MCInst TmpInst0;
+    MCInstLowering.Lower(I, TmpInst0);
     OutStreamer.EmitInstruction(TmpInst0);
-  } while ((I != E) && I->isInsideBundle()); // Delay slot check
+  } while ((++I != E) && I->isInsideBundle()); // Delay slot check
 }
 
 //===----------------------------------------------------------------------===//
diff --git a/llvm/lib/Target/Mips/MipsInstrFormats.td b/llvm/lib/Target/Mips/MipsInstrFormats.td
index c026b5d..6977e45 100644
--- a/llvm/lib/Target/Mips/MipsInstrFormats.td
+++ b/llvm/lib/Target/Mips/MipsInstrFormats.td
@@ -366,12 +366,6 @@ class LUI_FM {
   let Inst{15-0}  = imm16;
 }
 
-class NOP_FM {
-  bits<32> Inst;
-
-  let Inst{31-0} = 0;
-}
-
 class JALR_FM {
   bits<5> rs;
 
diff --git a/llvm/lib/Target/Mips/MipsInstrInfo.td b/llvm/lib/Target/Mips/MipsInstrInfo.td
index f9e3af5..7e33cb1 100644
--- a/llvm/lib/Target/Mips/MipsInstrInfo.td
+++ b/llvm/lib/Target/Mips/MipsInstrInfo.td
@@ -918,8 +918,7 @@ def CLO : CountLeading1<"clo", CPURegsOpnd>, CLO_FM<0x21>;
 def WSBH : SubwordSwap<"wsbh", CPURegsOpnd>, SEB_FM<2, 0x20>;
 
 /// No operation.
-/// FIXME: NOP should be an alias of "sll $0, $0, 0".
-def NOP : InstSE<(outs), (ins), "nop", [], IIAlu, FrmJ>, NOP_FM;
+def NOP : PseudoSE<(outs), (ins), []>, PseudoInstExpansion<(SLL ZERO, ZERO, 0)>;
 
 // FrameIndexes are legalized when they are operands from load/store
 // instructions. The same not happens for stack address copies, so an
-- 
2.7.4